I watched a colleague once, sat in front of what was then the latest, most powerful personal computer, with a spreadsheet on the screen, and he was actually counting on his fingers.
After a few minutes he realised I was there and in response to my bemused expression he eaplained that he was working on a French tanslation of our company's software and was figuring out how best to abbreviate some of the technical terms to fit into the field lengths available.....